Life-saving system

ABSTRACT

When a person  55  having a portable transmitter  41  hanging from his neck happens to fall into water, the self-contained sensor detects invasion of water into the transmitter  41  to send a water-detection signal to the on board transmitter-and-receiver system  42 . The engine drive control  45  is connected to the on board transmitter-and-receiver system  42 A, controlling the engine  47  so as to make the boat  46  retrace the way to the accidental point at which the transmitter wearer  55  fell into water, so that the boat  46  may stop close to him on water. The transmitter-and-receiver system  42  is equipped with a GSP system, so that it may inform selected people of predetermined addresses of the time and the place at which the person fell into water via a selected local station  202  by wireless. A life-saving article such as a life belt is made to fall onto water, and a rope ladder may be hang on the side of the boat  46  to permit the person to return to the boat by climbing the rope ladder.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a life-saving system, and more particularly, to a life-saving system for preventing persons from being left alone after falling from an on-water transport means such as an engine-powered boat into water in the sea or lake or for informing persons on board of someone falling into water.

[0003] 2. Related Art

[0004] When people get leisure time, they often have pleasure of riding in engine-powered boats. Then, one or more persons ride in an engine-powered boat for fishing. It may happen that the person who can drive the boat falls into water, leaving on board the others who cannot drive the boat.

[0005] Referring to FIG. 20, a person 11 fishing on board falls into water, allowing his boat to leave him behind as the engine is kept running. The person 11 cannot catch the boat because the boat moves swifter than he swims. As a result he will be alone in water in several ten seconds after falling into water, and he may be drowned to death. The boat is allowed to run until the fuel has been exhausted, and it may be lost.

[0006]FIG. 21 is a graph published by the Maritime Safety Board, Japan, showing how often accidents took place at sea every year, and how many people died at sea every year in this country. The same tendency is supposed to be observed everywhere in the world. In the worst case both of persons and boats are lost. Therefore, there has been an increasing demand for preventing such accidents at sea.

[0007] Japan Patent Application Laid-Open No. H 5-278680 proposed a life-saving system as shown in FIG. 22. An on-board wireless set 22 continues to communicate with the portable transmitters 24A and 24B carried by the persons 23A and 23B on board. These portable transmitters 24A and 24B communicate with plural satellites 25 to locate their instantaneous positions. Assuming that one person 23B falls into water, the transmitter 24B stops communication with the on-board wireless set 22, thereby informing the others of his falling into water. At the same time, the engine 26 is made to stop. The on-board wireless set 22 informs the others on board of the instantaneous position of the person falling in water, thereby permitting them to locate and save him on water.

[0008] There is, however, a problem that cannot be solved by the life-saving system proposed in Japan Patent Application Laid-Open No. H 5-278680 and shown in FIG. 22. Assuming that the boat driver falls into water. It takes a relatively long time for his portable transmitter 24B to stop its operation in water; the portable transmitter 24B can radiate the electromagnetic wave while it remains a relatively short depth from the water surface, and its operation cannot be made to stop until the portable transmitter has been sunk deep enough to allow water to invade inside, thereby preventing radiation of the electromagnetic wave. Therefore, the on board wireless set 22 continues to receive the electromagnetic wave from the portable transmitter for the while. In order to save the battery power the portable transmitter 24B may be so designed that it may radiate electromagnetic wave once every several seconds or once every minute. In such an intermittent radiating type of portable transmitter it takes still long time to be aware of the person falling into water.

[0009] Even though the engine is made to stop immediately after being aware of the person 23B falling into water, the person 23B is left behind, as far as several hundred meters apart from the boat 21. Accordingly it takes much time to save him, and there is a fear of losing his life. In a case where only one person rides in the ship, the person falls into water, and then, nobody remains on board to save him. A similar worst condition may arise if children or persons who cannot drive the boat are left on board. When the weather or the sea is raging, people on board cannot locate the person in water, and the person in water cannot find the boat 21 in the rough sea, either and cannot swim and reach the boat.

SUMMARY OF THE INVENTION

[0010] In view of the above, one object of the present invention is to provide a life-saving system responsive to the falling of a person into water for making the boat stop in the vicinity of the person in water.

[0011] Another object of the present invention is to provide a life-saving system responsive to the falling of a person into water for informing people other than those remaining on board of the falling of the person into water.

[0012] Still another object of the present invention is to provide a life-saving system so improved that the probability with which a person falling into water can be saved can be significantly improved.

[0013] Specifically in a life-saving system according to one aspect of the present invention a transmitter is attached to the body of every person on board, comprising a water-detector section and a wireless-transmission section responsive to the signal from the water-detector section for sending a predetermined water-detection signal, whereas the boat is equipped with engine stopping means, which is responsive to the predetermined water-detection signal for stopping the engine of the boat, thereby permitting the person on water to swim and reach the boat, and preventing the boat to be lost by allowing it to run with nobody on board.

[0014] In a life-saving system according to another aspect of the present invention a transmitter is attached to the body of every person on board, comprising a water-detector section, and a wireless-transmission section responsive to the signal from the water-detector section for sending a predetermined water-detection signal, whereas the boat is equipped with: a wireless set responsive to reduction of the electric power in the power source or battery of the transmitter below a certain limit for sending a power shortage warning signal; an engine stopping means responsive to the predetermined water-detection signal for stopping the engine of the boat; and engine-drive stopping means responsive to the power shortage warning signal for stopping the engine-drive, thereby permitting the person on water to swim and reach the boat, and preventing the non-attendant boat to be lost, and permitting the person to change the exhausted battery in time, thus preventing the boat from being put in inoperative condition because of the shortage of the battery.

[0015] In a life-saving system according to still another aspect of the present invention a transmitter is attached to the body of every person on board, comprising a water-detector section and a wireless-transmission section responsive to the signal from the water-detector section for sending a predetermined water-detection signal, whereas the boat is equipped with life-saving article releasing means responsive to the signal from the water-detector section for lowering life-saving articles on water, thereby permitting the person on water to swim and catch the life-saving article even though the boat runs far from the person.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Now, the present invention will be described in detail with reference to the accompanying drawings, in which:

[0017]FIG. 1 illustrates a life-saving system according to one embodiment of the present invention;

[0018]FIG. 2 is a perspective view of the portable transmitter;

[0019]FIG. 3 is a bottom view of the portable transmitter, showing the water detector section;

[0020]FIG. 4 is a front view of the portable transmitter, taken along the line A-A in FIG. 3 and partly broken to show the water detector section;

[0021]FIG. 5 shows the portable transmitter as not being soaked in water, thus simulating the state of the transmitter wearer being on board;

[0022]FIG. 6 shows the portable transmitter as being soaked in water, thus simulating the state of the transmitter wearer falling into water;

[0023]FIG. 7 is a block diagram showing the circuit structure of the portable transmitter in the life-saving system;

[0024]FIG. 8 illustrates separable parts of the receiver used in the life-saving system;

[0025]FIG. 9 is a block diagram showing the circuit structure of a wireless set or receiver provided on the boat;

[0026]FIG. 10 is a flowchart showing the manner in which the portable transmitter is controlled;

[0027]FIG. 11 is a flowchart showing the manner in which the wireless set or receiver is controlled;

[0028]FIG. 12 illustrates a life-saving system according to one modification of the present invention;

[0029]FIG. 13 is a block diagram, showing the circuit arrangement of a wireless set or transmitter-and-receiver used in the modification of the present invention;

[0030]FIG. 14 illustrates a life-saving system according to another modification of the present invention;

[0031]FIG. 15 is a block diagram of the portable transmitter used in the modification of FIG. 14;

[0032]FIG. 16 is a flowchart showing the manner in which the portable transmitter is controlled in the modification of FIG. 14;

[0033]FIG. 17 illustrates a life-saving system according to still another modification of the present invention;

[0034]FIG. 18 illustrates how the second releasing solenoid-and-plunger works, and how a life-saving article, that is, a life belt is hung from the plunger;

[0035]FIG. 19 illustrates a life-saving system according to yet still another modification, showing how far the person is floating after a short time subsequent to generation of the water-detection signal;

[0036]FIG. 20 illustrates that a person falls into water;

[0037]FIG. 21 shows how many accidents took place at sea and how many people died at sea in Japan; and

[0038]FIG. 22 shows how a conventional life-saving system works.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0039] Referring to FIG. 1, a life-saving system according to one embodiment of the present invention includes: a portable transmitter 41 equipped with an antenna inside (not shown); a receiver 42 having first, second, third and fourth switches 44A, 44B, 44C and 44D equipped therewith; a power supply 43 associated with the receiver 42; and an engine drive control 45 connected to the first switch 44A. The receiver 42 receives a water detection signal from the portable transmitter 41, which is sent from the portable transmitter 41 when put into water. In place of connecting the engine drive control 45 to the first switch 44A it may be possible that a solenoid 51 be connected to the first switch 44A via an associated power supply (not shown), thereby permitting the valve 49 to close and stop the feeding of fuel to the engine 47. Which type of control is adopted depends on the type of the boat that is equipped with the life-saving system. In FIG. 1 the connection between the first switch 44A and the solenoid 51 is shown by broken lines.

[0040] The first switch 44A is responsive to the water detection signal from the portable transmitter 41 for closing its contacts for 15 seconds. The other switches 44B to 44D are responsive to the water detection signal for turning the power supply (not shown) off or keeping their contacts closed until associated reset switches (not shown) are depressed. Therefore, if the second switch 44B is connected to an emergency lamp 52 via the power supply 43, the emergency lamp 52 turns on when a person 55 having a portable transmitter 41 with him falls into water. Likewise, a siren 63 may be connected to the third switch 44C via the power supply 43, the siren 63 sounds when a transmitter wearer 55 falls into water. In the drawing the fourth switch 44D is not used.

[0041]FIG. 2 shows the portable transmitter 41 in appearance. It has a battery and different circuits built in its water-proof plastic casing, and the transmitter body 61 has a length of strap 63 passing through the top hole 62, and the strap loop has a slider-and-stopper 64 thereon. The transmitter body 61 has a power button 65, a power indicator 66 and an emergency button 67 appearing on its front, and a water sensor 68 partly appearing on its bottom. Thus, the portable transmitter 41 may hung from the neck by the strap 63 with the water sensor 68 directed downward.

[0042]FIGS. 3 and 4 show the water sensor from the different angles of view. As may be understood from these drawings, the transmitter body 61 has two electrodes 71 and 72 embedded in its bottom, which are exposed in the recesses 73 and 74 both made on the bottom of the transmitter body 61.

[0043] Referring to FIG. 5, the transmitter body 61 is above the water surface when the person wearing the personal transmitter 41 rides in the boat. In this position the two electrodes 71 and 72 are isolated by surrounding air, not allowing an electric current to flow therebetween even if the voltage is applied to these electrodes from the battery 82. Thus, the ampere meter 83 shows no current.

[0044] Referring to FIG. 6, the transmitter body 61 is at least partly sunk into water when the person wearing the personal transmitter 41 falls into water. In this position water invades in the inter-electrode space to allow an electric current to flow therebetween, as indicated by the ampere meter 83. This indicates that a person has fallen into water.

[0045] Referring to FIG. 7, the portable transmitter 41 includes a transmission control section 91 comprising a CPU (central processor unit), a RAM and a ROM. The transmission control section 91 executes a control program stored in the ROM, thereby effecting a required control in the portable transmitter 41.

[0046] When the power button 65 is depressed, the transmission control section 91 is put in circuit with the self-contained battery 92 to make the power indicator 66 turn on. The voltage of the self-contained battery 92 is applied to a remaining quantity detector circuit 93, which can make a decision as to whether the voltage is of normal value or below a certain limit at which the battery needs to be changed. The remaining quantity detector circuit 93 directs a voltage decision-making signal to the transmission control section 91. In a case where the voltage of the self-contained battery 92 is of normal value, that is to say, the self-contained battery 92 stores the quantity of electric power large enough to allow the transmission control section 91 to work three or more days, the power indicator 66 keeps its light emitting diode (not shown) giving out light continuously. In a case where the self-contained battery 92 can afford to supply sufficient quantity of electric power to the transmitter no longer than two days, the power indicator 66 causes its light emitting diode to flicker. In almost all cases engine-powered boats return to their harbors in three days, and therefore, the certain limit below which the battery power is regarded as being deficit is determined as above described; the transmission control section 91 may be most probably kept energized by the electric power still available from the battery until the boat returns to the harbor within three or less days.

[0047] When it is necessary to change the battery, the transmission control section 91 allows the light emitting diode of the power indicator 66 to flicker, thereby inducing the transmitter wearer to change the self-contained battery 92 in his portable transmitter 41. Assuming that when the boat is far out at sea, and that the light emitting diode starts flickering, the battery is changed in the boat. If no battery is available in the boat, the portable transmitter can probably continue to work until the boat returns to the harbor.

[0048] A clock circuit 96, an emergency button 67, a water sensor 68, a voltage regulator 97, a resetting circuit 98 and a transmitter circuit 99 are connected to the transmission control section 91. An antenna circuit 101 is connected to the transmitter circuit 99. The clock circuit 96 directs time-and-day signals to the transmission control section 91. The voltage regulator 97 applies a controlled voltage of constant value from the self-contained battery 92 to different parts of the transmitter 41. The resetting circuit 98 permits the transmitter wearer to reset the transmission control section 91 when the transmitter works abnormally. The voltage regulated by the voltage regulator circuit 97 is applied to the transmitter circuit 99, which sends the water-detection signal when the transmitter 41 is put into water.

[0049] Referring to FIG. 8, the receiver 42 comprises a receiver body 111 and a fixing metal plate 112. The receiver body 111 and the fixing metal plate 112 are fixed together with screws 113. The receiver 42 is fixed to a wall in the engine room or to any other place convenient to the operator. Specifically the fixing metal plate 112 is fixed to the receiver body 111 with screws 113, and then the fixing metal plate 112 is fixed to the wall (not shown). The receiver body 111 may be hung on the wall in place of being fixed with screws. In view of the vibration from the engine or the rolling and pitching of the boat it is preferred that the receiver 42 be fixed firmly to the wall with the fixing metal plate 112 and screws 113.

[0050] As seen from the drawing, the receiver 42 has the power switch 121, resetting switch 122, first to fifth switches 44A to 44D and a speaker 123 on its front. The power switch 121 and the first to fifth switches 44A to 44D have their indicators 124 and 125 above for indicating their being used. The antenna 126 is fixed to the top of the receiver body 111 for receiving the electromagnetic wave radiated from every portable transmitter 41. The speaker 123 is responsive to the water-detection signal for sounding or uttering an oral message, thereby telling them how to deal with the matter. The emergency lamp 52 or siren 53 may be optionally connected to any of the second to fourth switches 44B to 44D so that other boats may be informed of the accident.

[0051] Referring to FIG. 9, the receiver body 111 includes a receiver control section 131 in which a CPU, a RAM and a ROM are installed. The receiver control section 131 executes the control program contained in the ROM, thereby effecting a required control on the receiver.

[0052] When the power switch 121 turns on, the power supply 43 in the form of electric generator is driven by the engine 47, and the voltage appearing at the output terminal of the power supply 43 is applied to the voltage regulator 132. Thus, the constant voltage is applied to the receiver control section 131. So far as the engine is running, the power supply 43 can supply electric power as required, and there is no fear of electric power shortage in the receiver 111, different from the portable transmitter 41 (see FIG. 1).

[0053] The receiver control section 131 is connected to a receiver circuit 134, which receives the electromagnetic wave via an associated antenna 126. Also, the receiver control section 131 is connected to an exterior outputting indicators 124, 125, a clock circuit 135, a timer circuit 136, a relay circuit 137, a resetting switch 122, a voice IC circuit 138 and a voltage regulator 132.

[0054] The clock circuit 135 provides the receiver control section 131 with clock signals and pieces of time information. The relay circuit 137 is responsive to the water-detection signal for magnetically energizing and self-holding. The relay circuit 137 can be released from the self-holding position by depressing the resetting switch 122 or by making the power switch 121 turn off. The timer circuit 136 is responsive to the magnetic energization of the relay circuit 137 for keeping the first switch 44A turning on for 15 seconds. In order that the boat 46 is made to stop by closing the valve 49 with the aid of the solenoid 51, it is necessary in almost all cases that the valve 49 be kept closed ten or more seconds to prevent the fuel from flowing to the engine 47, as described above by referring to FIG. 1. In view of this, the first switch 44A is designed to be kept closed fifteen seconds or somewhat longer than required in this particular embodiment.

[0055] In a case where the engine drive control 45 is equipped with an extra switch or an electronic switching device for stopping the engine 47. The first switch 44A can be connected to such extra switch (or such electronic switching device) directly or via an extra electronic device, thereby permitting such extra switch to stop the engine 47 immediately in response to a predetermined electric signal when received.

[0056] The voice IC circuit 138 is connected to the receiver control section 131, and the voice IC circuit 138 stores voice or sound data for emergency use. The voice signal from the voice IC circuit 138 is directed to the amplifier 139, and the so amplified voice signal is directed to the speaker 123. The oral message thus reproduced by the speaker 123 is given, as for example follows: “Help! Someone falls into water.” “Please dial such and such telephone number immediately.” Such telephone numbers can be stored in an associated memory medium, which permits the writing of data therein. Speakers (not shown) other than the speaker 123 can be used for the same purpose. The voice IC circuit 138 may be attached to the receiver body 111 as optional, and may be so designed as to permit selection of a desired oral message among those stored in the memory.

[0057] Referring to FIG. 10, the portable transmitter 41 of the life-saving system works as follows: a decision is made as to whether or not the water sensor 68 of the transmission control section 91 detects invasion of water (S151); in the negative, a decision is made as to whether or not the emergency button 67 is depressed (S152); in the negative a decision is made as to whether or not the remaining power quantity detector circuit 93 detects the lowering of the voltage of the self-contained battery 92 below a certain threshold (S153); and in the negative a decision is made as to whether or not the resetting circuit 98 is put in operation (S154). When the water sensor 68 detects invasion of water (S151), the transmitter wearer 55 is supposed to have fallen into water (FIG. 1), allowing the transmitter circuit 99 to send a water-detection signal (S155).

[0058] When the transmitter wearer 55 depresses the emergency button 67 (S152), the transmitter circuit 99 sends a water-detection signal (S155). In a case where the water sensor 68 fails to work, the transmitter wearer 55 depresses the emergency button 67.

[0059] In a case where the remaining power quantity detector circuit 93 detects the lowering of the voltage of the self-contained battery 92 below a certain threshold (S153), the power indicator 66 is made to flicker (S156). In a case where the resetting circuit 98 is put in operation (S154), all proceedings are reset (S157).

[0060] Referring to FIG. 11, the receiver of the life-saving system works as follows: a decision is made as to whether or not the water-detection signal is received (S171); in the affirmative, the relay circuit 137 is energized, and at the same time, the timer circuit 136 and the voice IC circuit 138 are put in operation (S172). This may be omitted if the receiver 111 is equipped with no voice IC circuit.

[0061] In a case where no water-detection signal is received, and in a case where the resetting switch 122 is operated (S173), the receiver circuit 134 interrupts the proceeding subsequent to reception of the water-detection signal (S174). This has the effect of preventing the engine 47 from stopping if the transmitter wearer 55 should inadvertently depress the emergency button 67.

The First Modification

[0062] Referring to FIG. 12, in a life-saving system according to the first modification of the present invention the wireless receiver 42A is so designed that it can receive the water-detection signal from a portable transmitter, and that it can communicate with a selected satellite 201 to locate the boat 46 (Global Positioning System). Also, the receiver 42A is so designed that in a case where a transmitter wearer happens to fall into water, the receiver can telephone selected persons such as members of his family via the nearest local station to inform them of the accident at sea.

[0063] In this particular modification the engine drive control 45A is responsive to the accidental signal from the portable transmitter 41 for reversing and stopping the engine 47, thereby making the boat 46 return to and stay at the place where the person fell into water. Specifically the boat 46 cannot stop immediately after the person fell into water, and usually the boat 46 stops apart from the place where the person 55 fell into water. The engine drive control 45A is equipped with a ROM table (not shown), which permits a required arithmetic operation to be effected on the basis of the speed at which and the direction in which the boat 46 is running before it stops, thus determining how far the boat is from the person in water, and determining how long the engine must be reversed to make the boat return to the place where the person fell into water. Thus, the boat 46 can come close to the person in water.

[0064] If the life-saving system relies on the Global Positioning System only, the boat can hardly come close to the person in water because the person 55 is apt to be carried away by the current or stream in the sea. In this particular modification it is assumed that the boat 46 and the person 55 are moved by the stream at same speed in same direction, and on this assumption the boat 46 is controlled to come close to the person in water. There is a fear of injuring the person in water by the propeller 204 of the boat 46 when the boat 46 is coming close to him. The boat 46 may be equipped with an extra propeller (not shown) for exclusive use in saving persons in water. Such extra propeller may be arranged at a place at which the person in water cannot get close to the extra propeller, or the extra propeller may be so shaped that it cannot injure the person in water. If there is no stream in water as in lakes, the engine drive control 45A may effect a required feedback control, relying on Global Positioning System only.

[0065] In this particular modification using Global Positioning System a message referring to the time and position at which the person fell into water can be prepared and sent to his family by wireless telephone. This permits the boat to ask other boats or airplanes to save his life.

[0066]FIG. 13 shows the structure of the transmitter-and-receiver 111A of the first modification, indicating same parts as in FIG. 9 by same reference numerals used in FIG. 9. Description of such same arts, therefore, is omitted. As seen from the drawing, it includes a transmitter circuit 211 and a transmission data compiling circuit 212, and the receiver circuit 134A is equipped with means for acquiring positional data from a selected satellite 201. The transmitter-and-receiver control section 131A has the same functions as the receiver control section 131 in FIG. 9.

[0067] The transmitter circuit 211 of the transmitter-and-receiver 111A can send pieces of information to a predetermined address via a selected local station 202, as described earlier. The contents of the pieces of information are those compiled by the transmission data compiling circuit 212. Specifically the transmission data compiling circuit 212 combines predetermined message with the time and place at which the person fell into water (compiling operation).

The Second Modification

[0068] Referring to FIG. 14, in a life-saving system according to the second modification of the present invention the potable transmitter 41B is so designed that it can transmit not only the water-detection signal when the transmitter wearer falls into water, but also a battery change signal when the voltage of the self-contained battery lowers below a predetermined threshold. The battery change signal may be produced as different from the water-detection signal to be sent to the receiver 42B. The fact that the transmitter wearer falls into water can be readily discernible from the fact that the self-contained battery is deficient in electric power, and therefore, in this particular modification one and same signal is used in common as representing the invasion of water in the transmitter and the shortage of electric power in the battery.

[0069]FIG. 15 shows the structure of the portable transmitter 41B. It is same as the portable transmitter 41 of FIG. 7 although the program contained in the transmission control section 91B is partly different from the one contained in the transmission control section 91 of FIG. 7.

[0070]FIG. 16 shows how the portable transmitter 41B is controlled. Same steps as in FIG. 10 are indicated by same reference numerals as used in FIG. 10, and descriptions of such same steps are omitted. A decision is made as to whether or not the remaining power quantity detector circuit 93 detects the lowering of the voltage of the self-contained battery 92 below a certain threshold (S153); in the affirmative the transmitter circuit 99 sends a battery change signal, which is same as the water-detection signal (S301), and at the same time, the power indicator 66 is made to flicker (S156).

[0071] Thus, the receiver 42B makes the engine 47 stop or be inoperative, as is the case with the accident at sea. When the transmitter wearer 55 rides in the boat to restart the engine 47, the engine 47 cannot start, or it stops soon once it has started. Then, the transmitter wearer 55 is aware of the flickering of the power indicator 66 to realize that the self-contained battery is deficient in electric power. Thus, he can change the battery without fail before the boat leaves the harbor. The portable transmitter can work for a while after the power indicator 66 begins to flicker, and it may be possible that the transmitter wearer is not aware of the flickering of the power indicator 66. Therefore, it may be necessary that the receiver be equipped with an emergency light 52 or siren 53 to warn him of the shortage of electric power in the battery, thereby preventing the worst incident in which the person whose transmitter is deficient in electric power falls into water.

[0072] In this particular modification when the boat 46 is far from the harbor, and when the battery is deficient, the boat 46 is made to stop. Then, he can change the battery for the new one if available. Depression of the resetting button (not shown) makes the remaining power quantity detector circuit 93 inoperative until the power supply turns on next time, preventing transmission of the water-detection signal due to the shortage of electric power in the battery. Then, the boat 46 can be driven as usual.

The Third Modification

[0073] Referring to FIG. 17, in a life-saving system according to the third modification of the present invention the receiver 42C is responsive to the water-detection signal from the portable transmitter 41 for making some life belts 401 fall from the opposite sides of the boat 46 onto water, and for releasing one end of the rope ladder 402 with the other end fastened to the side of the boat. The life belt 401 is of expanded styrol, plastics or wood, and is painted with phosphorus paint or noticeable color. One end of an elongated rope 403 is fixed to the life belt 401, and the other end of the rope 403 is fastened to the motor-driven reel 404 to be wound therearound.

[0074] The rope 403 covers the distance measured from the point at which the boat 46 running at its maximum speed begins to stop to the point at which the boat stops. Such distance is 50 to 100 meters long. When the life belt 401 falls into water, the motor-driven reel 404 rotates freely, unwinding the rope while the boat is running. When the receiver 42C receives a rope-winding signal, an electric motor associated with the reel starts winding.

[0075] The receiver 42C is equipped with the first, second, third and fourth switches 44A to 44D. The engine drive control 45 is connected to the first switch 44A, and it makes the engine stop in response to reception of the water-detection signal.

[0076] The second and third switches 44B and 44C are connected to the ladder-releasing solenoid 411 and life belt-releasing solenoid 412, and these solenoids are responsive to the water-detection signal for releasing one end of the rope ladder 402 and the life belt 401 respectively.

[0077] Referring to FIG. 18 the life belt-releasing solenoid 412 is a large-sized waterproof plunger-and-solenoid. As shown, the plunger 412A projects from the solenoid 412 with its end put in the hole made in one leg of the “U”-shaped frame 421, and the life belt 401 is hung from the plunger 412A.

[0078] When the life belt releasing solenoid 412 is energized, the plunger 412A is pulled back into the solenoid 412, thereby allowing the life belt 401 to fall onto water. The ladder-releasing solenoid 411 is similar to the life belt-releasing solenoid 412 in structure. Similar releasing operation, however, can be attained by appropriate electric means other than the solenoid-and-plunger 412, such as electromagnetic valve or motor.

[0079]FIG. 19 illustrates how the situation is like after a short time subsequent to the falling of a transmitter wearer 55 into water. The boat 46 is not far from the transmitter wearer 55 in water, and the water-detection signal is received by the on board receiver 42, so that the first to third switches 44A to 44C may be put in operation. Thus, the engine is made to stop, the ladder 402 is released by one end to be suspended from the boardside, and the life belt 401 falls onto water.

[0080] The boat 46 continues to move for a while, leaving the person behind. But, the life belt 401 remains there at the place where it fell onto water. In a case where the life belt floats along with the stream, the person floats along with the stream, too, and therefore, the life belt 401 remains a short distance enough for the person to swim and catch it.

[0081] After catching the life belt 401 the person 55 applies the terminals of the portable transmitter 41 to a pair of terminals 422 of the life belt (see FIG. 18), and he pushes the emergency button (see FIG. 2). Then, the portable transmitter 41 sends a rope-winding signal to the receiver 42C to actuate the fourth switch 44D. Then, the rope 403 is wound to pull the person 55 toward the boat 46.

[0082] The life belt 401 may be equipped with a rope-winding signal generator (not shown). Otherwise, the life belt 401 may have an electric resistor connected across the paired terminals 422, and the life belt 401 may be equipped with means responsive to connection of the electric resistor across the counter paired terminal of the transmitter for sending to the on board receiver a signal representing the situation of the person 55 catching and wearing the life belt 401.

[0083] When the person 55 is pulled close to the boat 46, he pulls the portable transmitter 41 apart from the life belt 401 to stop transmission of the rope-winding signal, and he climbs the rope ladder 402.

[0084] If the life belt 401 happens to leave the person 55 for unknown reasons, and if the portable transmitter 41 is disconnected from the paired terminals 422 of the life belt 401, the winding of the rope is intermitted to prevent the life belt 401 from being pulled toward the boat 46, leaving the person 55 behind. As explained above, a quick return to the boat by winding the rope 403 and climbing the rope ladder 402 can be effective for the person 55 from a point to avoid attack of a shark.

[0085] The water-detection signal is generated at the instant when the water sensor detects invasion of water in the portable transmitter 41. In order to prevent a wrong detection the portable transmitter may be so designed that it may send the water-detection signal after a while subsequent to the continuous detection of water invasion. In order to save the self-contained battery 92 the water-detection signal may be sent intermittently as for instance, follows: the signal is sent one second after every five second-long intermission, thereby permitting a significant elongation of the battery life.

[0086] The embodiment and modifications are described as radiating the electromagnetic wave at the time the water-detection signal is sent from an outside an outside antenna, but conversely it may be possible that the electromagnetic wave be radiated all the time except for detection of water invasion, which is informed by interruption of the electromagnetic wave. This requires much electric energy, and accordingly the life of the battery is shortened. The safety, however, can be assured significantly. In addition, an antenna can be an inside antenna that disposed inside of the device.

[0087] The fuel-feeding valve is described as being controlled with the aid of associated solenoid, but it may be controlled by appropriate means other than the solenoid, such as motors.

[0088] In the third modification the life belt 401 is described as having an elongated rope 403 attached thereto. The rope, however, may be omitted. As an alternative a small-sized lifeboat or a raft may be used. Such life-saving article may be provided with a wireless transceiver, food and water for emergency use. In addition, by means of wearing of a life jacket together with the use of a life-saving system of the present invention, safety of a person can be raised more.

[0089] As may be understood from the above, the life-saving system according to the present invention a person falling into water can save his life by himself or persons on board even though he does not wear a life jacket. The boat can be made to stop even if nobody remains on board or even if nobody else can drive the boat. Thus, the non-attendant boat cannot be lost, or cannot be allowed to run uncontrolled and crush other boats before the fuel is exhausted.

[0090] In a case where the remaining electric power of the self-contained battery lowers below a certain threshold, the engine cannot be started, and therefore, a transmitter wearer can change the battery without fail before traveling on water.

[0091] The portable transmitter may be so designed that it is responsive to water invasion for sending a water-detection signal by wireless, and accordingly the life of the self-contained battery can be saved.

[0092] Conversely the portable transmitter may be so designed that it continues to radiate the electromagnetic wave all the time except for occurrence of the accident or shortage of the self-contained battery. This may improve the life-saving degree attained by the life-saving system.

[0093] The portable transmitter may be so designed that it outputs the water-detection signal intermittently, thereby elongating the life of the self-contained battery long enough to permit the transmitter to continue the sending of the emergency signal while the transmitter wearer is floating a long length of time on water.

[0094] An arithmetic operation is effected to determine how long a distance the boat must retrace to the accidental point at which a transmitter wearer fell into water from the stop point at which the boat stops, and the engine is so controlled according to the arithmetic determination that the boat may retrace the way to the accidental point. The retracing of the boat to the accidental point is most effective in saving his life, compared with the case of allowing the boat to stay and wait for him; the way to the boat is reduced to possible minimum, and accordingly the saving probability can be improved significantly.

[0095] The life-saving system may be equipped with a wireless emergency informing means, which is responsive to a water-detection signal for addressing pre-selected people or some rescuers. Then, pieces of information may be combined with some pre-prepared messages, and so compiled information may be sent by wireless. This permits the quick, extensive rescue to be attained.

[0096] The life-saving system may comprise a warning sound generating means responsive to the water-detection signal for generating warning sound, thereby informing surrounding people of occurrence of an accident. This is most effective when it fogs.

[0097] The life-saving system may comprise a warning light generating means responsive to the water-detection signal for projecting a beam of light, thereby informing surrounding people of occurrence of an accident. This is most effective when it is dark at night.

[0098] The portable transmitter may be equipped with an extra button, which allows the transmitter to send a signal similar to the water-detection signal when the extra button is depressed. In a case where the water sensor does not work or where a transmitter wearer on board is aware of someone else falling into water, the extra button can be depressed, thus causing the life-saving activity to start quickly before the boat leaves the person on water behind far away.

[0099] The life-saving system may comprise life-saving articles responsive to the water-detection signal for departing from the boat onto water, thereby permitting the person to swim and catch the life-saving article on water. When the life-saving article floats along with the stream, the person floats along with the stream, too. Therefore, the distance between the life-saving article and the person remains short enough to reach. Assuming that a person falls into water in winter, the boat cannot stop before running 50 to 100 meters, increasing the difficulty with which the person wearing winter clothes can swim and catch the boat. The short distance to the life-saving article on water contributes largely to the saving of his life. The rope ladder hung on the side of the boat helps him climb the boat by himself. Such rope ladder is wound and set neatly on the side of the boat, not giving unpleasing appearance.

[0100] A life belt is fastened to the boat with an elongated rope, which is wound and set neatly on the side of the boat. When the person swims to catch the life belt, he can be pulled toward the boat by the rope.

[0101] The rope is long enough to cover the distance from the accidental point to the stop point at which the boat stops after the engine is made to begin stopping. Thus, the life belt cannot be moved apart from the person by allowing the boat to pull the rope after running the distance equal to the length of the rope. The stopping of the boat and falling of the life-saving article contributes greatly to reduction of the number of people drowned to death.

[0102] The boat may be equipped with means for withdrawing a life-saving article subsequent to the catching of the article by a person on water, thereby permitting the person to return to the boat without consuming his physical power.

[0103] The boat may be equipped with such life-saving articles on its opposite sides and at its stern, thereby permitting a selected article or articles to fall in the vicinity of the person on water. Assume that only one life-saving article is hung on one side of the boat, and that it is released to fall into water while the person fell into water on the other side of the boat. When the boat runs a long distance apart from him, the person finds the article on water. It is difficult that he swims to catch the article on the wrong side, and the difficulty increases largely when the sea is rough. 

What is claimed is:
 1. A life-saving system characterized in that it comprises: a portable transmitter means including, in its body, a detector for detecting water, a transmitter section responsive to detection of water by the detector for sending a predetermined water-detection signal by wireless, and a power supply for putting the transmitter means in operation, and means for wearing the portable transmitter means to the body of a person; and an engine stopping means responsive to the water-detection signal for stopping the engine of an on water transporting means.
 2. A life-saving system characterized in that it comprises: a portable transmitter means including, in its body, a detector for detecting water, a power supply for putting the transmitter means in operation, a remaining power quantity detecting means for detecting the lowering of the remaining power quantity of the power supply below a certain threshold, a wireless transmitter section responsive to detection of water by the detector for sending a water-detection signal, and responsive to detection of the lowering of the remaining power quantity of the power supply below the certain threshold for sending a power shortage signal, and means for wearing the portable transmitter means to the body of a person; and an engine stopping means responsive to the water-detection signal and the power shortage signal for stopping the engine of an on water transporting means.
 3. A life-saving system according to claim 1 or 2 wherein the portable transmitter means sends the water-detection signal only while the water detection is being made.
 4. A life-saving system according to claim 1 or 2 wherein the portable transmitter means prevents the water-detection signal from being sent for a predetermined length of time while the water detection is being made.
 5. A life-saving system according to claim 3 or 4 wherein the water-detection signal is sent intermittently.
 6. A life-saving system according to claim 1 or 2 wherein the engine stopping means comprises analytical means for determining analytically how the engine is to be controlled to make the on water transporting means return to the position at which the on water transporting means received the water-detection signal, and an engine drive control means for controlling the engine according to the analytical determination.
 7. A life-saving system according to claim 1 or 2 wherein it further comprises an emergency wireless-communication means responsive to the water-detection signal from the portable transmitter for informing people of predetermined addresses by wireless.
 8. A life-saving system according to claim 1 or 2 wherein it further comprises a warning sound generating means responsive to the water-detection signal from the portable transmitter means for informing people of occurrence of an accident with sound.
 9. A life-saving system according to claim 1 or 2 wherein it further comprises a warning light projecting means responsive to the water-detection signal from the portable transmitter means for informing people of occurrence of an accident with light.
 10. A life-saving system according to claim 3 wherein the portable transmitter means has an extra button provided thereon, depression of which extra button permits the portable transmitter to send a signal similar to the water-detection signal.
 11. A life-saving system characterized in that it comprises: a portable transmitter means including, in its body, a detector for detecting water, a transmitter section responsive to detection of water by the detector for sending a predetermined water-detection signal by wireless, and a power supply for putting the transmitter means in operation, and means for wearing the portable transmitter means to the body of a person; and means responsive to the water detection signal for making at least one life-saving article fall onto water from an on water transporting means.
 12. A life-saving system according to claim 11 wherein the life-saving article is a life belt and a length of rope, one end of which is fastened to the life belt and the other end of which is fastened to the on water transporting means.
 13. A life-saving system according to claim 12 wherein it further comprises an engine stopping means responsive to the water-detection signal for stopping the engine of the on water transporting means, the length of the rope being longer than the distance from the point of position at which the life belt fell to the point of position at which the on water transporting means stops after the engine is made to begin stopping.
 14. A life-saving system according to claim 11 wherein the on water transporting means comprises a life-saving article withdrawing means responsive to a predetermined signal for withdrawing the life-saving article.
 15. A life-saving system according to claim 14 wherein the life-saving article withdrawing means comprises means for winding the length of rope fastened to the life-saving article.
 16. A life-saving system according to claim 11 wherein the means for making at least one life-saving article fall onto water from the on water transporting means makes a plurality of life-saving articles fall onto water.
 17. A life-saving system according to claim 1, 2 and 11 wherein the on water transporting means has a ladder means provided thereon, the ladder means being responsive to the water-detection signal from the portable transmitter means for falling onto water, thereby permitting a person falling into water to return to the on water transporting means. 